Psychophysical experiments are proposed to examine color mechanisms beyond the traditionally studied first (receptor) stage and second (linear opponent-process) stage. Higher order nonlinear mechanisms have been shown to play a role in the detection of color changes, color induction and transient desensitization. Little is known, however, about their chromatic, spatial, temporal and adaptation properties. We propose to study these properties using novel stimuli generated on a computerized display system. The experiments we propose include (i) measurements of modulation of threshold for detection of color changes as a function of the chromatic modulation of the background, (ii) increment threshold measurements of flashed fields following transient desensitization along theoretically defined color directions, and (iii) measurements of color induction for spatially complex inducing stimuli and for centers with complex shapes. These experiments will provide information about (i) the rules of combination of cone signals at later stages of the visual system, (ii) the multiplicative and subtractive processes of color adaptation, and (iii) the spatial properties of the contrast and averaging processes of color induction.